Alternate seriesname seperator

Add the ability to replace spaces in the seriesname with an alternate (e.g. a ".") without changing the spaces elsewhere in the name.

# Example Usage:

In config set
* 'use_alternate_seriesname_seperator': True,
* 'alternate_seriesname_seperator': '.',
* 'filename_with_episode': '%(seriesname)s.S%(seasonnumber)02dE%(episode)s - %(episodename)s%(ext)s',

For an output format of
* Law.&.Order.S01E01 - Prescription for Death.avi