IOBuffer documentation fixes.
[autodoc] Some toplevel documentatioon for Cache.
Changed PCHARP ptr to be a void*.
Added a new sscanf low-level API: It is now possible to sscanf using pcharp formats/strings.

This makes it possible to call sscanf on partial strings and similar tricks.
Moved __builtin.IOBuffer to Stdio.IOBuffer (for now)
The IOBuffer documentation now extracts
Fixed direct call of cast.
Fixed direct call of cast.
Fixed direct calls to cast.
Represent G_TYPE_POINTER as an integer to prevent segfaults
Ensure something's pushed for every argument to a GTK2 signal callback
GTK2: Update Scale docs based on source file
GTK2 docs formatting fix
Added a PCHARP version of the json parser.

Also added a new flag: JSON_FIRST_VALUE.
If this is set data after a value is ignored.
Added read_json method.

It will read the first json value on the stream and return it.
Ignore the generated file
Use pike_sizeof instead if _sizeof.
Fixed the indexing-fallback-code of map on objects.
Calendar: Improved dwim_time() for ISO-8601 dates.

Also adds some corresponding testsuite tests.

FIXME: Ought to have tests for all the patterns in dwim_{day,time}().
On second thought, this is so obscure that we shouldn't probably do it at all.