all: first stab to full scientific notation support
Merge pull request #7 from gonuts/dev/complete-scientific-notation

all: first stab at full scientific notation support
hcl: stop number if whitespace

/cc @sbinet - The issue was in the lexer. It was seeing:

1.2e-10
e =

As:

1.2e-10e
Fix broken parsing case
hcl: identifiers can have '-'
hcl: fix scenario where infinite loop happens