Improve parameter parsing so it doesn't break the scheduler on weird parameter values

Adds failing unit test exposing broken parameter split
Merge pull request #149 from spotify/freider/broken_param_split

Improve scheduler-side parameter parsing
Adds unit tests for db_task_history, bug fixes

Uses sqlite3 in memory mode for db.
If sqlalchemy can't be imported, skips the test rather than failing.
Server logs with timestamp archived in daily files
Merge pull request #156 from spotify/freider/server_log_spooling

Server logs with timestamp archived in daily files
Merge pull request #151 from JoeEnnever/db_fix

Adds unit tests for db_task_history, bug fixes
added File.copy

Use case: when a file, e.g. from an ExternalTask lives
on a read-only filesystem, you cannot `move` it.

One unittest included.
Merge pull request #158 from miku/feature/filecopy

added File.copy