Add an identifier_to_id() method

Per #261.
Clear APC before parsing, not after

Closes #342.
Make view tracking optional

Provide a constant (RECORD_VIEWS) and employ it within
Law::record_view(). Closes #266.
Add a sample XSLT
Correcting description of creation
An initial round of environment-sanity tests

Per #273.
Test whether a downloads directory can be written to

Per #273.
Send environment test errors to the logger

Log the errors, but rather than bailing on the method at that point,
continue. This allows the display of all errors at once, rather than
requiring that people laboriously work through a series of them. Per
#273.
Add another level of mod_rewrite sanity checking

Per #273. This helps with servers that don't permit
apache_get_modules(), but it doesn't yet tell us whether AllowOverride
permits use of RewriteEngine in .htaccess.
Test whether RewriteRules are being respected

Ridiculous hackery. Create a testing-only alias to index.php via
RewriteRule, and then request that alias during the server environment
sanity checks. Per #273.
Fix a PHP error
Determine the request protocol in a different way

Per #273.
Don't forget ://

Per #273.
Test that cURL is installed

Per #273.
Eliminate port testing

It turns out that $_SERVER['SERVER_PORT'] is actually checking the
requested port, not the port that's served up. Vagrant translates 8080
requests to 80—Apache doesn't know anything about 8080—but SERVER_PORT
still reports that it's 8080. Disabling for now, will revisit when
addressing #275.

Per #273.
Suppress cURL output
Light cleanup
Only run the parser if the server environment is sane

Per #273.
Disable MultiViews in the API

This solves an issue raised in #273.
If the database doesn't exist, redirect to the admin section

Per #274 and #289.