Roadmap implementation for v2

[justinwilaby]

This PR provides the following for v2 of sax-wasm:

• Improved performance up to 63%
• Angular 2+ html template support
• Processing instructions, doctype, comments and SGML declarations now contain start and end positions
• Removed the majority of unsafe rust

Breaking changes:

• SaxEventType.CDATA must be used to retrieve CDATA values which are now of type Text
• SaxEventType.SGMLDeclaration, SaxEventType.Doctype, SaxEventType.ProcessingInstruction and SaxEventType.Comment now return Text objects
• Objects passed to the event handler read directly from the wasm memory buffer instead of copying from it. Persisting these objects for long periods of time could result in a memory access error. This was a trade-off when making a huge jump in performance.

[coveralls]

Pull Request Test Coverage Report for Build 251

• 51 of 52 (98.08%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-1.7%) to 93.048%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/js/saxWasm.ts	51	52	98.08%
<!--	Total:	51	52	98.08%	-->

Totals
Change from base Build 245:	-1.7%
Covered Lines:	128
Relevant Lines:	132

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💛 - Coveralls