Case sensitive search

Add tool button menu to FindReplaceWidget with an entry to select
case sensitive search.
Avoid duplicates of texts in constants. Save state of 'Show special characters' flag. Do not save defaults for point size and tab width.
Fixed word wrap logic and changed default to true
Whole words only and RegExp search (#63)

Added two more actions to tool button menu in FindReplaceWidget. With
these actions the user can activate searching only for whole words and
searching using regular expressions.
Merge branch 'develop' into feature/search-options-#63
Merge branch 'feature/search-options-#63' into develop
Make constants uppercase. Move them to top of file
Add more built-in snippets
Merge branch 'feature/103_SaveNoDefaults' of https://github.com/Slesa/CuteMarkEd into slesa-feature/103_SaveNoDefaults

Conflicts:
	app/options.cpp
Added more comments for translators
New function: goto line
Line calculation implemented as cloose mentioned. Use constants for readability
Merge pull request #114 from Slesa/feature/GotoLine

Add "go to line" menu item.

Add a new menu item "Go to Line" that allows the user to position the cursor to a specific line in the Markdown document.