Minor changes, mostly to documentation. Several bug fixes.

Minor changes, mostly to documentation. Several bug fixes.

In the README file:
- Converted reference to xuni version 1.0.0 to 0.3.0
- Updated the website for xuni from theprogrammingsite to SourceForge
- Added mention of git instead of svn
- Re-worded "garbage collector" and the "ANSI standard" paragraph

Changes to source code:
- Made get_angle() take a pointer to the <angle> tag, simplifying it somewhat
- Added binary_insertion_sort() to utility.c
    - This replaces the bulk of memory_find_data()
    - It could make () easier in the future
- Removed the very old and commented-out print_sizes() from xuni.c
- Experimented with alternative ways to rescale text to the right ratios
- get_real_pos() now takes a double instead of an int
- Removed the currently-unused wtype_t::type (and the one reference to it)

Bug fixes:
- Added validate_xuni_structure(), which detects when:
    - No root widget is present (which is currently a fatal error)
    - No themes have been loaded (this should use a default theme -- with
        primitives?)
- parse_resource() used to segfault when no resource files could be loaded
- Failing to load an XML resource file is no longer marked as a fatal error

Doxygen documentation:
- gui.c (new: 3 functions)
- utility.c (new: 1 function)
- font.c (modified: 1 function)
- widget.c (new: 4 functions)

Changes to XML resource files:
- Removed old, spurious <theme> element from editor.xml
- Added test widgets to gui/editor.xml, such as a grid checkbox

Other changes:
- Simplified filecount.sh -- it no longer uses perl, just a flag to make