Added external documentation files.

Added initial quick tutorial, compatibility appendix, transition guide
and external main page.

docs/Doxyfile.in

@@ -655,7 +655,7 @@ WARN_LOGFILE           = @GLFW_BINARY_DIR@/docs/warnings.txt
 # directories like "/usr/src/myproject". Separate the files or directories
 # with spaces.
 
-INPUT                  = @GLFW_DOC_HEADERS@
+INPUT                  = @GLFW_DOC_HEADERS@ @GLFW_SOURCE_DIR@/docs/
 
 # 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
@@ -673,7 +673,7 @@ INPUT_ENCODING         = UTF-8
 # *.hxx *.hpp *.h++ *.idl *.odl *.cs *.php *.php3 *.inc *.m *.mm *.dox *.py
 # *.f90 *.f *.for *.vhd *.vhdl
 
-FILE_PATTERNS          =
+FILE_PATTERNS          = *.dox
 
 # 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.
@@ -1115,7 +1115,7 @@ ECLIPSE_DOC_ID         = org.doxygen.Project
 # navigation tree you can set this option to NO if you already set
 # GENERATE_TREEVIEW to YES.
 
-DISABLE_INDEX          = YES
+DISABLE_INDEX          = NO
 
 # The GENERATE_TREEVIEW tag is used to specify whether a tree-like index
 # structure should be generated to display hierarchical information.
@@ -1127,7 +1127,7 @@ DISABLE_INDEX          = YES
 # Since the tree basically has the same information as the tab index you
 # could consider to set DISABLE_INDEX to NO when enabling this option.
 
-GENERATE_TREEVIEW      = YES
+GENERATE_TREEVIEW      = NO
 
 # The ENUM_VALUES_PER_LINE tag can be used to set the number of enum values
 # (range [0,1..20]) that doxygen will group on one line in the generated HTML