Extract parameters from methods, constructors and functions

[nknapp]

This commit adds a property "ctx.params" (an array of strings)
to the parsed comment..

The rationale is that the @param-tags are not necessarily in the same
order as the parameters in the code. In the case of

/**
 * @param {number} a
 * @param {string} b
 */
function myFunction(b,a) {
}

it would otherwise not be possible to create the correct documentation
(that shows the correct order of the parameter)

[nknapp]

Maybe consider this work-in-progress. I just realized, that there are a couple of cases that would break with this change.

/**
 * @param a
 * @param b
 */
function abc(a, ...b) {} 

/**
 * @param a
 * @param b
 * @param c
 * @param d
 */
function abc(a, {b,c,d}) {}

/**
 * @param a
 */
function abc(a /* , dynamic args */) {}

The question is, do you actually want to support this? Otherwise I would just use my own fork.