Closes #1627

Closes #1531

This reverts commit 0c39409da710ede162c873616d7295242ccc4981.

added _SIG macros

Previously they could conflict with user-defined type traits that
were in the global namespace.

Fixes #1548

Previously, for a TEMPLATE_PRODUCT_TEST_CASE("Test" ..., T, (P1, P2)),
the generated test case names were

  Test - 0
  Test - 1

With this commit, the correct typename is used:

  Test - T<P1>
  Test - T<P2>

-----------

MSVC needs another indirection to evaluate INTERNAL_CATCH_STRINGIZE
and also inserts a space before theINTERNAL_CATCH_STRINGIZE_WITHOUT_PARENS
parameter, which we can get rid of by pointer arithmetic.

support for generating test cases based on multiple template template
types combined with template arguments for each of the template template
types specified

e.g.
```
TEMPLATE_PRODUCT_TEST_CASE("template product","[template]",
			   (std::tuple, std::pair, std::map),
			   ((int,float),(char,double),(int,char)))
```
will effectively create 9 test cases with types:
std::tuple<int,float>
std::tuple<char,double>
std::tuple<int,char>
std::pair<int,float>
std::pair<char, double>
std::pair<int,char>
std::map<int,float>
std::map<char,double>
std::map<int,char>

Tested type is accessible in test case body as TestType
Unique name is created by appending ` - <index>` to test name
since preprocessor has some limitations in recursions

Closes #1454

This adds support for templated tests and test methods via
`TEMPLATE_TEST_CASE` and `TEMPLATE_TEST_CASE_METHOD` macros. These
work mostly just like their regular counterparts*, but take an
unlimited** number of types as their last arguments.

* Unlike the plain `TEST_CASE*` macros, the `TEMPLATE*` variants
require a tag string.

** In practice there is limit of about 300 types.