added maca_lexer a program that recoginzes non ambiguous mwe

CMakeLists.txt

maca_common/CMakeLists.txt

maca_common/include/trie.h

maca_common/include/util.h

maca_common/src/trie.c

maca_lexer/CMakeLists.txt

maca_lexer/src/context.c

maca_lexer/src/context.h

maca_lexer/src/extract_mwe_from_fplm.c

maca_lexer/src/maca_lexer.c

maca_tokenizer/main.c

maca_tokenizer/tok_rules.l