Save tagged needs fixing

[phastmike]

Save tagged lines works only if we are hiding untagged lines (based on that model). A workaround fix is to enable the hide_untagged_lines method before saving. Another option is to keep track if line is tagged but will have more overhead.

[phastmike]

hide_untagged_lines toggles state and not always the same result. This may lead to showing all lines (if already hiding untagged) which results in a similar file as the original one.

[phastmike]

Fix for the workaround - dev branch ( commit: 14a13b5 ). Needs better solution.