Fix #299

When no input filename is given, the path is not actually
retained. This commit fixes this based on the suggested
edit of @jborch in #299.
uiputfile: also accept .tikz files by default
uiputfile: removed newline in call
Merge branch 'fix299'
Fix #300: support tick labels with commas
Merge branch 'fix300'
prepare 0.4.5