Closes #126

There is actually no bug in MinGW. The different behaviour under Windows is
expected, because the implicit conversion there is only to std::wstring.

Macroprocessor: make the removal of “@#line” directives and extra newlines consistent across LF and CR+LF conventions

Simplify the algorithm using only regexps, and add comments.

This completes the separation of parse trees from their evaluation.

Closes: #32

This only concerns the situation when `savemacro` is also passed.

When `linemacro` is passed, the macro expanded .mod file is the same as before

When `linemacro` is not passed, the macro expanded .mod file is equivalent to what it was before when both `noemptylinemacro` and `nolinemacro` were passed.

closes #44
closes #45

ancillary to this change is the move of `paths` out of the Driver class into an argument to parsing/evaluation #32

Before this commit, a dynare call such as
```
dynare <<mod file>> -Db=“A” -Da=@{b}
```
would not expand the value of `b` in `a` whereas
```
dynare <<mod file>> -Da=“A” -Db=@{a}
```
would expand the value of `a` into `b` because the arguments were stored in a map which printed the `@#define` statements in the .mod file in alphabetic order.

This feature is ill-designed and no longer needed by the GUI. And is not very
useful: it is not possible to interact with the preprocessor without using the
filesystem, since the preprocessor creates many files anyways.

If we really need to reimplement such a feature, it should rather be redesigned
by reading the modfile from standard input (cin). That could be triggered by
using "-" as the filename argument (as is already done by several standard Unix
utilities).

Usage: ./dynare_m $'<<mod file text>>'

The $’’ expands special characters. This is necessary because our setup for native matlab statements require that they end with a newline. In other words, the rest of the mod file can be sent on one line, but if there is a native matlab statement you must enter a `\n` after it.

NB: In this case, apostrophes must be escaped: ' becomes \'

e.g., to run tests/example1.mod:
./dynare_m  $'//Example 1 from Collard\'s guide to Dynare\nvar y, c, k, a, h, b;varexo e, u;verbatim;% I want these comments included in\n% example1.m 1999q1 1999y\n%\nvar = 1;\nend;parameters beta, rho, alpha, delta, theta, psi, tau;alpha = 0.36;rho   = 0.95;tau   = 0.025;beta  = 0.99;delta = 0.025;psi   = 0;theta = 2.95;phi   = 0.1;\nmodel;c*theta*h^(1+psi)=(1-alpha)*y;k = beta*(((exp(b)*c)/(exp(b(+1))*c(+1)))*(exp(b(+1))*alpha*y(+1)+(1-delta)*k));y = exp(a)*(k(-1)^alpha)*(h^(1-alpha));k = exp(b)*(y-c)+(1-delta)*k(-1);a = rho*a(-1)+tau*b(-1) + e;b = tau*a(-1)+rho*b(-1) + u;end;initval;y = 1.08068253095672;c = 0.80359242014163;h = 0.29175631001732;k = 11.08360443260358;a = 0;b = 0;e = 0;u = 0;end;shocks;var e; stderr 0.009;var u; stderr 0.009;var e, u = phi*0.009*0.009;end; stoch_simul;'