Replace "Duplicate address in symbol list" error with warning
Properly escape quotes in quoted strings, throw on errors

This breaks compatibility with most saved profile data, since
symbol names containing spaces are rather common.
Sleepy now throws on malformed data instead of parsing it incorrectly.
Quote symbol names in saved profiles

This fixes loading profiles (created with this version or newer)
which contain symbols with space characters.
Check for trailing data in Symbols.txt
Replace concatWithChar(s, c) with s.push_back(c)
Update Changelog
Add Copy menu item to the right-click menu
Fix per-line counters
Finalize version 0.90

...and begin version 0.91