[WIP] removing pysqlcipher sources from the repo.

Travis builds are taking too long due to double installations of pysqlcipher,
the second installation which runs from pip seems to be doing fine now, if there
are any issues left in pysqlcipher we'll fix them upstream as suggested by @dionyziz
Merge pull request #755 from gubatron/bye-bye-pysqlcipher-sources

removing pysqlcipher sources from the repo.