always build feature complete

[psychocrypt]

Change

• throw an error if a compile dependancy is not fullfilled
• add options to disable hard compile dependancies

close #14

Note

I used the names *_REQUIRED to mirroring the fact that if someone disable the requirement of a dependancy it is still build with those if they can be found.

Expert Option

All libraries which are searched with cmake find_package can be disabled with CMAKE_DISABLE_FIND_PACKAGE_<PackageName>. If for example OpenSSL is disabled the error is thrown that the used needs to disable the requirement.
example how to disable OpenSSL also if the library is available: cmake ../xmr-stak-nvidia/ -DCMAKE_DISABLE_FIND_PACKAGE_OpenSSL=ON -DOpenSSL_REQUIRED=OFF

Test

• compiled test
• runtime test

[fireice-uk]

Thanks!