Add support for LFE

[KrzysiekJ]

I offer a small bounty of 120 BLK (worth about $28 at the time of writing) to whoever implements a lexer of Lisp Flavoured Erlang. Rules:

1. To claim the bounty, include payment address in the commit message, submit a pull request to this repository and reference this issue.
2. Bounty expires on September 5th 2017 (UTC).
3. lfe-mode will be treated as a primary reference in reviewing the lexer.
4. Repository’s contributing guidelines prevail.
5. Bounty will be paid in seven days.

[aalvrz]

Hm this seems fishy...

[stale]

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