[TAP] Fix memory issues for the 'text/plain' format.

The previous text formatting process was storing the entire table in memory....
hence OutOfMemoryError when dealing with large table.

Now, this process is done entirely in memory only for a table having less than
1000 lines. For a larger table, its content is stored in a temporary file. This
file is deleted after usage or in case of error.

This formatting process has been tested under JVM monitoring (both JConsole and
VisualVM) and tables larger than 3,000,000 rows, with success.

This commit fixes the GitHub issue #40