cangjie: Factor code in cangjie_get_filter_query

The OR logic has been extracted in a separate function.
cangjie: Style (spacing) changes from dridi's last commit

This is really minor nitpick.
Merge branch 'strcat_or_operator'

I'm merging manually:
    https://github.com/Cangjians/libcangjie/pull/53#issuecomment-32003137