persistent lock utitlity and intergration (microsoft#33)

* lock standalone utility

* seperate linux/windows code, and change some format

* add comments

Author: azhao155

apache2/Makefile.am

@@ -6,6 +6,7 @@ mod_security2_la_SOURCES = acmp.c \
     ag_mdb/ag_mdb.cpp \
     waf_logging/waf_format.pb.cc \
     waf_logging/waf_log_util.cc \
+    waf_lock/waf_lock.cpp \
     apache2_config.c \
     apache2_io.c \
     apache2_util.c \