…n modern OS X

…ersions

Not all current NodeJS installs return "node" when checking
`process.argv[0]`.

On my system it returns:

$ node -p -e 'process.argv[0]'
/Users/glenn/.nvm/versions/node/v4.2.2/bin/node

Do the sniff-test of whether we are running tests in a browser or
in node a different way.

An example of previous fail was:

```
/Users/glenn/src/miniLockLib/library.compiled/readSliceOfData.js:17
        this.fileReader = new FileReader;
                              ^

ReferenceError: FileReader is not defined
    at EncryptOperation.module.exports [as readSliceOfData] (/Users/glenn/src/miniLockLib/library.compiled/readSliceOfData.js:17:31)
    at EncryptOperation.module.exports.EncryptOperation.encryptData (/Users/glenn/src/miniLockLib/library.compiled/EncryptOperation.js:161:19)
    at EncryptOperation.module.exports.EncryptOperation.run (/Users/glenn/src/miniLockLib/library.compiled/EncryptOperation.js:85:19)
    at EncryptOperation.module.exports.EncryptOperation.start (/Users/glenn/src/miniLockLib/library.compiled/EncryptOperation.js:78:16)
    at EncryptOperation.start (/Users/glenn/src/miniLockLib/library.compiled/EncryptOperation.js:4:59)
    at Object.miniLockLib.encrypt (/Users/glenn/src/miniLockLib/library.compiled/index.js:19:22)
    at /Users/glenn/src/miniLockLib/tests.compiled/A Few Demo Tests.js:15:26
    at /Users/glenn/src/miniLockLib/tests.compiled/fixtures.js:50:14
    at Object.read.files.basic.txt (/Users/glenn/src/miniLockLib/tests.compiled/fixtures.js:56:14)
    at exports.read (/Users/glenn/src/miniLockLib/tests.compiled/fixtures.js:46:28)
```

…ADME.

Revised the introduction of the Digging In section to explain that GNU
Make and Node.js are the basic software requirements for fiddling with
the miniLockLib code.

Removed pointer to “brew install …” because i don’t like alcohol or the
command line.

…t’s why i am removing it.

Reverts commit 3d06d2f

Running `make` works on my computer when the browserify package is
installed locally with `npm`. i am willing to consider other options if
this doesn’t work predictably on other computers.