put all softsusy classes and functions into the softsusy namespace

This avoids conflicts with user-defined functions and variables.
Merge branch 'nmssm2' into softsusy-namespace

Conflicts:
	physpars.cpp
	physpars.h
	utils.h
Merge branch 'softsusy-namespace' into nmssm2
fix most compiler warnings (found with -Wall -Wextra)

Two warnings remain:

 * two unused variables in nmssm1loop.f:jacobi

 * missing braces around initializer { 0 }
   This warning is gcc bug #53119 .
Started the introduction. Few changes to abstract etc too
Bug fix: must not read the SLHA line again

In the SLHA file the line

  Block EXTPAR  # Input parameters
      0   2.71524254e+16       # MX scale

was read twice like

  int i; double d;
  kk >> i >> d;
  kk >> i >> d;

which lead to undefined values of i and d.
Merge branch 'nmssm2' into SMuonMix