docs: Major clean up of doxygen generated core API documentation

To make the API documentation usable (again):

  - Rename to "FreeSWITCH API Documentation"

  - Remove all external INPUT paths, only scan FreeSWITCH core sources

  - Only parse a sane subset of files: *.c *.cc *.cpp *.h *.hh *.hxx
    (don't care about any python / whatever files for now)

  - Exclude modules (seriously, all the mod_java / mod_managed stuff
    turned it into an unusable mess. You need API docs of modules? Add separate doxygen
    configurations for them (or specific ones))

  - Include src/mod in example search path (for @include etc.), add C/C++
    patterns.

  - Set up PREDEFINED to fix the massive clusterf*ck that was caused by
    SWITCH_DECLARE() and friends.

<End Of Rant>
Signed-off-by: Stefan Knoblich <s.knoblich@axsentis.de>

docs/Doxygen.conf

@@ -25,7 +25,7 @@ DOXYFILE_ENCODING      = UTF-8
 # The PROJECT_NAME tag is a single word (or a sequence of words surrounded
 # by quotes) that should identify the project.
 
-PROJECT_NAME           = FreeSWITCH
+PROJECT_NAME           = "FreeSWITCH API Documentation"
 
 # The PROJECT_NUMBER tag can be used to enter a project or revision number.
 # This could be handy for archiving the generated documentation or
@@ -568,8 +568,7 @@ WARN_LOGFILE           =
 # directories like "/usr/src/myproject". Separate the files or directories
 # with spaces.
 
-INPUT                  =../src ../libs/libdingaling ../libs/esl \
-			../libs/openzap ../libs/libteletone
+INPUT                  =../src
 
 # This tag can be used to specify the character encoding of the source files
 # that doxygen parses. Internally doxygen uses the UTF-8 encoding, which is
@@ -586,7 +585,7 @@ INPUT_ENCODING         = UTF-8
 # *.c *.cc *.cxx *.cpp *.c++ *.java *.ii *.ixx *.ipp *.i++ *.inl *.h *.hh *.hxx
 # *.hpp *.h++ *.idl *.odl *.cs *.php *.php3 *.inc *.m *.mm *.py *.f90
 
-FILE_PATTERNS          =
+FILE_PATTERNS          = *.c *.cc *.cxx *.cpp *.h *.hh *.hxx *.hpp
 
 # The RECURSIVE tag can be used to turn specify whether or not subdirectories
 # should be searched for input files as well. Possible values are YES and NO.
@@ -598,7 +597,7 @@ RECURSIVE              = YES
 # excluded from the INPUT source files. This way you can easily exclude a
 # subdirectory from a directory tree whose root is specified with the INPUT tag.
 
-EXCLUDE                =
+EXCLUDE                = ../src/mod
 
 # The EXCLUDE_SYMLINKS tag can be used select whether or not files or
 # directories that are symbolic links (a Unix filesystem feature) are excluded
@@ -626,14 +625,14 @@ EXCLUDE_SYMBOLS        =
 # directories that contain example code fragments that are included (see
 # the \include command).
 
-EXAMPLE_PATH           = ../conf
+EXAMPLE_PATH           = ../conf ../src/mod
 
 # If the value of the EXAMPLE_PATH tag contains directories, you can use the
 # EXAMPLE_PATTERNS tag to specify one or more wildcard pattern (like *.cpp
 # and *.h) to filter out the source-files in the directories. If left
 # blank all files are included.
 
-EXAMPLE_PATTERNS       = *.xml
+EXAMPLE_PATTERNS       = *.xml *.c *.cc *.cpp *.h *.hh *.hxx
 
 # If the EXAMPLE_RECURSIVE tag is set to YES then subdirectories will be
 # searched for input files to be used with the \include or \dontinclude
@@ -1266,7 +1265,29 @@ INCLUDE_FILE_PATTERNS  =
 # undefined via #undef or recursively expanded use the := operator
 # instead of the = operator.
 
-PREDEFINED             =
+PREDEFINED             =SWITCH_DECLARE(type)=type \
+			SWITCH_DECLARE_NONSTD(type)=type \
+			SWITCH_DECLARE_DATA= \
+			SWITCH_DECLARE_CLASS= \
+			SWITCH_DECLARE_CONSTRUCTOR= \
+			ESL_DECLARE(type)=type \
+			ESL_DECLARE_NONSTD(type)=type \
+			ESL_DECLARE_DATA= \
+			TELETONE_API(type)=type \
+			TELETONE_API_NONSTD(type)=type \
+			TELETONE_API_DATA= \
+			SPAN_DECLARE(type)=type \
+			SPAN_DECLARE_NONSTD(type)=type \
+			SPAN_DECLARE_DATA= \
+			STFU_DECLARE(type)=type \
+			STFU_DECLARE_NONSTD(type)=type \
+			STFU_DECLARE_DATA= \
+			FT_DECLARE(type)=type \
+			FT_DECLARE_NONSTD(type)=type \
+			FT_DECLARE_INLINE(type)=type \
+			FT_DECLARE_DATA= \
+			__declspec(x)= \
+			__attribute__(x)=
 
 # If the MACRO_EXPANSION and EXPAND_ONLY_PREDEF tags are set to YES then
 # this tag can be used to specify a list of macro names that should be expanded.