0.8.0

Migration to LLVM 11.
Add multiple return values and group declarations.
Add automatic documentation generator (-docs flag).
Add debug allocator.
Add new FileSystem module.
Add #import directive for modules
Add BL Doctor for better unit testing.
Add first prototype of modules and #import hash directive.
Add support of shebang and silent execution.
Add -silent and -rs options.
Add -verify-llvm option to enable LLVM IR verification.
Add modules: thread, sync, fs
Add forward of command line arguments into bl executed by interpreter (-r, -rs).
Add multithread compilation.
Support custom allocators in containers.
Compiler now returns numerical maximum error code if compilation fail.
Less descriptive terminal output during compilation.
Fix segfault on error get line.
Fix invalid character when comment block is very last in source file.
Fix garbage in unknown symbol reports.
Fix attempt to generate type info for incomplete types referenced by aliases.
Fix invalid multi-line string literals parsing.
Fix usage of function call to initialize loop iterator.
Fix invalid generation of more complex PHI expressions.