#1 fixed.

Implemented the following behavior:
When I do a clean install the Destinations->Image uploader->Imgur is checked, but Destinations->Image uploader->File uploader->Dropbox is not checked.
If I click on items inside Destinations->Image uploader->File uploader then the behavior must be as is, that is Destinations->Image uploader->File uploader must be checked to show me that item inside is selected.
Now if I click on items inside Destinations->Image uploader other than File uploader then all items inside File uploader must be unchecked to avoid misleading me.
If Imgur is selected and I click on Destinations->Image uploader->File uploader then some item inside must be checked automatically. If there was previous selection then it must be set. If there were no previous selections than first item in the list must be checked by default.
#1 fixed the same issue but for the text uploads menu.
Merge pull request #283 from barsv/fix_1_menuChecks

Change check behavior for Destinations->Image uploader->File uploader
there is a problem - submenu item gets checked when parent menu item is checked.
fix for the problem - when you restart the application the last selected submenu item gets checked.
remove unnecessary using
applied changes to TaskSettingsForm. reused code from MainForm.
removed unnecessary code that remained after making ImageFileDestination, TextFileDestination not nullable.
Added comments
fix comment
Merge pull request #284 from barsv/fix_1_menuChecks

Code improvements and fixes for pull request "Change check behavior for Destinations->Image uploader->File uploader #283"
Added Pastebin login status label
Improved Pastebin UI
fixed #285: Image effects will be enabled by default
Added Chevereto image uploader support
Chevereto direct URL support
Merge pull request #33 from ShareX/master

Update from base