Use QPlainTextEdit for log window rather than QTextEdit

It is only used for plain text and is much more light weight that the
full text edit class.
Refs #7331
Re #9030. Removed unused classes.
Re #9030. Use covariance matrix to estimate errors of calc. values
Re #9030. Added a unit test
Re #9030. Changed getCovarianceMatrix to return a const Matrix
Re #9030. Use chi squared in error calculation
refs #8060 Created Muller Ansatz template

with contents equal to Strontium122
refs #8060 should have Ansatz function defined.
refs #8060 intermediate checkout

Ansatz looks more or less reasobable but looking at proper identification for external references
refs #8060 All formally here

The question is how to test all this to be sure it is all right.
refs #8060 Attempt to fix Unix error
refs #8060 Fixing unix warnings.
Added algorithm PoldiPeakSearch

The algorithm is very close to the original fortran program. There are
still some tests/documentation missing.
Added checks for edge cases, completed unit tests
Chose some more clear variable names, added a few comments
Added check for minimum peak separation
Small typos and fix for TIB at CNCS. Refs #9122
refs #9135 This should fix the issue
refs #8060 should fix bunch of CPP check warnings
Moved comment about background to appropriate location