Bugfix

[cooliscool]

Fixing bugs mentioned in #12

1. https://github.com/bradford-hamilton/dora/blob/master/pkg/parser/parser.go#L211-L216
   An Error in the input string is detected, but forgets to return, causing an infinite for loop.

2. https://github.com/bradford-hamilton/dora/blob/master/pkg/parser/parser.go#L302-L307
   An Error in the input string is detected, but forgets to return, causing an infinite for loop.

3. https://github.com/bradford-hamilton/dora/blob/master/pkg/lexer/lexer.go#L166-L169
   l.char == 0 breaks the loop if 0 is found in JSON payload, but l.advanceChar() which was already done before that causes l.position to get incremented causing the slice to hit out of bound.

4. https://github.com/bradford-hamilton/dora/blob/master/pkg/parser/parser.go#L314-L319
   An Error in the input string is detected, but forgets to return, causing an infinite for loop.