Adding tweet map support

- Added (optional) tweet map, which shows predefined place names on a
map and allows drill-down to tweets based on a text search for that
place name.
- Fixed an issue where tracking keywords would be counted as stopwords
if the stem of the keyword differed from the original word.
- Set default values for a few non-null fields that caused query
problems when deploying CT on Windows (but not on Linux - way to go
MySQL).
- Added shell scripts for starting and stopping CT without AIDR.