A bunch of fixes and improvements

I've got one more of these to go, and then we are moving into beta territory.

Fifth alpha release

This release contains mostly fixes, and some improvements, most notably:

• New: Session library.
• Renamed: aeImage::cover() to aeImage::fill().
• Changed: Options library works differently now and triggers error when option name is mistyped.
• Deprecated: ae::launch() and ae::utilize() in favour of ae:register().

Fourth alpha release

Database fixes and improvements:

• SQL statements can be used instead of values.
• Only dirty values are saved to database when entity is saved.
• Queries can be logged now.

Probe library has been updated to log queries in one statement rather than three. ;-)

Third alpha release

• All core libraries are sufficiently documented now.
• File library is on par with PHP's stock file functions.
• Quite a few other fixes and improvements.

Second alpha release

Improve caching, naming, and fix some bugs.

First alpha release

After 2 years in the making I declare this an alpha. ;-)