[ENH] [FIX] Added default values for BUILD_* local variables. Removed header from the list of lib4neuro source files.

[FIX] Removed 'filesystem' header causing problems with portability. CI pipeline on CentOS (issue #25) is active.

CentOS Dockerfile repo: git@github.com:MartinBeseda/centos-ci.git

[ENH] Compiled libraries are now always in the folder build/lib, examples in build/examples and tests in build/tests independently of Debug/Release compilation mode. The compilation problems with Lapack on Windows (see issue #21) are also solved in this version - Lapack and BLAS binaries contained in Armadillo repository are being linked, if not set up explicitly.

[FIX] [WIP] [WIN] Fixed compilation on Windows in Release mode. Linking boost_unit_test library does not work well - we must use include version of Boost.test so far.

[WIP] [BUILD ERROR] [WIN] Trying to get working compilation on Windows. Problems with building tests and running examples - they seem to stop in the middle of the code.

[WIP] [FIX] [WIN] Fixed problem with -j flag in *.bat build files (issue moldyn/lib4neuro#8). Now trying to get Lapack downloaded and compiled automatically on Windows.

[FIX] [CODE]: Fixed initialization of 'optimal_parameters' in LearningSequence::optimize() method. Commented out compilation with AddressSanitizer.

[ENH] [RUNTIME ERROR]: moved 'optimal_parameters' variable and its getter to the LearningMethod class.