Update node-process version number.
Pass "flags" option to each transform

Essentially, "flags" is set to the value of the bundler's
"_options" property.

This should enable more intelligent transform behaviours,
for example toggling source maps when --debug is supplied
through the CLI or module API.

* Closes substack/node-browserify#844
* Fixes hughsk/uglifyify#16
* Fixes hughsk/uglifyify#18
Make source map "sourceFile" relative to "basedir"
Add type check for `opts.basedir`
respect expose option of require, fixes #839
array external test
array external
5.12.2
Merge branch 'master' of github.com:substack/node-browserify
Merge branch 'transform-flags-opts' of https://github.com/hughsk/node-browserify
_flags
document transform opts, opts._flags
5.13.0
Merge branch 'patch-2' of https://github.com/ForbesLindesay/node-browserify
5.13.1
Merge branch 'relative-source-map-path' of https://github.com/zertosh/node-browserify
6.0.0
Merge branch 'master' of https://github.com/ds82/node-browserify
6.0.1
Merge branch 'patch-1' of https://github.com/jtangelder/node-browserify