Fixed bug with recursive transformation in blocks

[paoloantinori]

Fixes #18

Approach:

• moved handling of block to the top of transformation, to avoid to have them already replaced by other rules
• extract blocks from the original text, and store them in a datastructure.
• place a temporary placeholder in place of the original block
• delegate to the rest of the transformations
• replace temporary placeholders with the stashed ones

[FokkeZB]

Awesome! Could you resolve the conflict in src/J2M.js?

[paoloantinori]

Here you go. Sorry, I hadn't noticed I was out of sync.