Create performance tests

To evaluate the efficiency of our database and system as a whole, we need to create some performance tests.
This can be seen as an extension of https://bugs.launchpad.net/glot/+bug/352792

Once we have dictionary importing (https://bugs.launchpad.net/glot/+bug/353547) and searching implemented, we should construct write a script that does something like 1,000,000 queries randomly from the imported items. For a while we will have less than 1,000,000 items in the database, so there will be some repetition.

We should also do varying types of queries. We should do simple word ones (eg "dog"), ones with more complex constraints ("dog in japanese from edict"), and more expansive ones ("from jpn to eng" <-- this should return all jpn->eng results).

We may want separate scripts to test the performance when it interprets a query string (as above) and when it simply sends queries directly to the database, so we can get more accurate numbers of both.

If possible, both processor time, clock time, and memory use should be calculated.

The first step in this bug is to merely run 1,000,000 simple word queries and get the clock time. The more interesting stuff can follow later.