Add Vim swap files to .gitignore
Add regression test's leftovers to .gitignore
Only use the 'line' variable for the to-be displayed line. Hence, copy line_randomed's address to 'line' if spice was requested.
Fix typo in information output. unusally -> unusually
Introduce new hotkeys for copying 'values' to clipboards.

'x' will copy to PRIMARY X selection,
'X' will copy to CLIPBOARD ("^C -> ^V") X selection,
't' will insert the value to tmux's paste buffer.

'x' and 'X' uses xclip(1): the 'value' is sent to its stdin.
't' uses the tmux binary of course, and it just calls the set-buffer
command with the 'value' as its parameter.

Both binaries must be in PATH, and if they can not be executed, an error
message gets printed to the user.

Removal of the 'values' from the clipboards are not being dealt with!!!
Fix logic flaw in saving the new database file.

We must reopen the new database as the ("old", closed after rename()d)
'db_file' file descriptor, and place a lock on it again, to avoid the
situation where after a 'write' command, the database would have been
saved alright, but the lock would have been dropped with the closing of
the old db_file (because of the rename()), and the new db_file wouldn't
have a file lock. So someone could have opened the now saved database
file also for writing in parallel with the original kc instance.

This should probably get merged in the 2.3 branch.