Merge pull request #260 from krues8dr/master

Fixed javascript links with parentheses
Eliminate unnecessary use of DIRECTORY_SEPARATOR

Per #219. (Or, rather, contra #219.)
Comment laws, structure, laws_views columns

I should have checked in these changes a while ago.
Cache the template file in PHP

Per #138.
Pull a count() out of a for() loop

To speed it up. Per #138.
Pull uses of count() out of for() loops

To speed them up, per #138.
Cache API keys in APC

Per #120. Note that this will need to be standardized come #172.
Minor code formatting improvements
Refactor url_to_structure to use structure_unified table

Closes #183.
Support illustration content types in the database

This provides no support beyond labelling the content accordingly. It
remains to be determined how to store the illustrations, how to display
them, etc.
Comment on api_keys columns

Per #220.
Make subsections textual by default
Comment on text columns

Per #220.
Comment on text_sections columns

Per #220.
Comment on text table

Per #220.
Comment on structure column, table

Per #220.
Comment on text table

Per #220.
Comment in laws_references column, table

Per #220.
Comment on dictionary table, columns, remove default

Per #220. Also, removed "chapter " as default scope for definitions,
since that's not appropriate for a structure-agnostic system.
Correct typo in column comment

Per #220.