Bug fixes, docs updates, some polishing

• Refer Travis CI and Coveralls in contribute docs
• Remove version from the documentation completely
• Unshallow the git repo as it is used for testing
• Ignore errors about non-existent bugzilla emails
• Better handle xmlrpclib errors during bug search
• Document bugzilla plugin stats in more detail
• Bugzilla test suite adjustments (split, asserts)
• Log kerberos error as a debug message
• Decode command line arguments from utf-8
• Filter returned bugs by email or name
• Moving bug from NEW to ASSIGNED is not returning
• Improve fixed bugs detection in bugzilla plugin
• Allow stats name detection from multiline docs
• Do not run 'make clean' in the pre-commit hook
• Support fetching large queries in jira plugin
• Document stats order specification in config