Fix typo in ibus-table-createdb man-page

"for for" -> "for"
When tabcreatedb.py is called without any options, print a usage message

Do not just show a cryptic backtrace.

Resolves: rhbz#1049760
See: https://bugzilla.redhat.com/show_bug.cgi?id=1049760
Merge pull request #23 from mike-fabian/print-usage-message-when-tabcreate-is-called-without-options

Print usage message when tabcreate is called without options