s/spellckeck/spellcheck

was this done on purpose? =P
Merge pull request #63 from unhammer/master

s/spellckeck/spellcheck
Add allow-pointer-lock, allow-popups, allow-top-navigation values to sandbox attribute.
Merge pull request #64 from Eyyub/add_sandbox_values

Add 3 values to sandbox attribute.
Fix sizes attribute to be compliant with the spec.
`Sizes takes now (number * number) list, delete type sizes
Work with a buffer rather than string concat.
Use Buffer.contents instead of Buffer.to_bytes and set buff size to 17.
Merge pull request #65 from Eyyub/fix_sizes_attribute

Fix sizes attribute to be compliant with the spec.
Use safe-string and fix some deprecation warnings.
Fix svg font element and attributes.