one more test

to make sure the sizes of the outputted buffers are working correctly.
interpret 0 length buffer as 0

...both for fromSM and toSM
findAndDelete

This function is used by the script interpreter. When OP_CHECKSIG is performed,
the signature is found and removed from the script.
npm test recursive by default
recommend recursive tests to run all tests
ensure output is buffer
build browser tests recursively
add coverage command to readme
cosmetic
script interpreter

The script interpreter has been translated from bitcoin core's C++ code. It has
been kept as similar as possible in order to be reasonably sure that it has
been copied correctly. Note that as of this commit, the translation has not
been tested against bitcoin core. Only extremely trivial tests that ensure that
nothing terribly wrong happens have been applied.

There are three relevant json files in bitcoin core that we will need to test
against:

script_valid.json
script_invalid.json
tx_valid.json
tx_invalid.json

Once we test against these files, and (likely) fix any bugs that will occur, we
can have greater confidence that the script interpreter is correct.

The commit of bitcoin core that this interpreter has been translated from is
this: b5d1b1092998bc95313856d535c632ea5a8f9104