Fixed compiler to produce correct(ish) variable table This commit fixes a number of issues w.r.t inlined blocks and variable tables: * inlined blocks were mis-detected, we have to use `#isInlinable` as the `#isInlined` actually return `false` always, * there we duplicated records in variable table because some blocks have been visitied more than once, * block-locals for inlined blocks in method have wrong offsets since method arguments were not take into the account. For example, before this commit `ExternalLibraryFunction >> ffiCall:` had completely bogus info when bytecode-compiled.

Implement `Context >> argAndVarNames` using compiler-recorded debug info This implementation overrides the one from stx:libbasic which never worked properly (and it's horribly complex).

Fix ParserFlags and STCCompilerInterface to work with out-of-tree builds ...in addition to old, in-tree builds. This requies searching in `'build' / Smalltalk configuration` as well.

Search for binary class libraries in `build/<target>` first This is to support out-of-tree builds which allow one to compile Smallalk/X for multiple targets out of one source tree (useful for testing)

#FEATURE by cg class: ParseError added: #position

#BUGFIX by stefan class: AssignmentNode added: #variableNodesDo:

#UI_ENHANCEMENT by cg class: Parser changed: #errorMessageForUndefined: #selectorCheck:for:positions: typos: genitive of class is class's - not classes.

#FEATURE by cg class: Breakpoint added: #method comment/format in: #method:

#REFACTORING by cg class: Explainer class withCRs eliminated hanged: #explain:in:forClass:short: #explainGlobalOrPoolVariable:inClass:short: #explainSelector:inClass:short: #fetchCommentOfMethod:

#BUGFIX by cg class: Explainer class changed: #explain:in:forClass:short: