Encode "~" character in url

[raineorshine]

Adding the "~" character to the end of a thought breaks the url refresh because it interferes with the Context View url encoding.

Steps to reproduce

• Add the "~" character to the end of a thought
• With the cursor on this thought, refresh the page

Current Behavior

• Cursor disappears
• Causes a "restoreSelection" error

Expected Behavior

• When the cursor is on a thought containing "~" and the page is refreshed, the cursor should be restored properly and no error should occur.
• The "~" should be encoded in the url if it is part of the value of a thought, and decoded when parsed out.
• Context View url encoding with unencoded "~" should be preserved. ~ is used to encode the Context View state in the URL so that the page can be refreshed and re-open in the Context View.

Enter Ctrl + Shift + S, or click the button in the toolbar to activate the Context View on a given thought. To give a thought multiple contexts, just add it to two different places in the thoughtspace.