Stable 0.0.7

1. Added individual list limits, which can be used when using one or multiple lists.
   For example, if you used:

UserAgent("firefox+ios", limit=5)

It would limit each list to 5 user agents, and two lists, bringing the total user agents 10.

2. Checks if user agent files exist.
3. Checks if user list empty in Random()

0.0.6 Stable

Fixed package issues