Ace fixes

[adamjimenez]

Fix issue where pressing undo after initial load, clears the editor.
Single undo for text that was typed over. Before it would delete and restore in two undos.
Upped initial undo limit from 50 to 500.

[coveralls]

Pull Request Test Coverage Report for Build 4518587577

Details

• 6 of 6 (100.0%) changed or added relevant lines in 4 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage increased (+0.03%) to 65.598%

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Files with Coverage Reduction	New Missed Lines	%
lib/text-operation.js	1	93.12%

Totals
Change from base Build 835215972:	0.03%
Covered Lines:	2314
Relevant Lines:	3381

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💛 - Coveralls