Refactor static analysis primitives

[guybedford]

The static analysis in the relocate loader has become quite overly-specific in terms of how it detects static require statements etc.

As a result, there are cases that will be missed due to these overly specific checks not applying to all cases.

For example:

var path;
path = require('path');
fs.readFileSync(path.resolve(__dirname, 'file.js'));

but:

var resolve;
resolve = require('path').resolve;
fs.readFileSync(resolve(__dirname, 'file.js'));

won't. While var resolve = require('path').resolve in the above will.

These inconsistencies can be fixed by refactoring these checks into common general functions that are used throughout simplifying the code and reducing the code size as well.

This would be a useful and beneficial refactoring to undertake.

[guybedford]

Fixed in #234.