Add options for providing the variances, an identity matrix , and user specified matrices as proposal densities

Deals with #507 and #112
Includes a unit test

Clarify manual on different/inconsistent ordering of variables used in description of decision rules

The previous description used the same variables to denote both declaration and DR order, thus confusing users.

new nostrict command-line option does not exit when there are more endogenous than equations (closes #2)

Closes #431

The preprocessor implementation of "shocks" is broken, and the ref. manual
entries are empty. Nothing is implemented in MATLAB files. It's better to
remove this for now, until a working implementation is done.

Ref. #136

Add information on the outputs of the static and dynamic model files