added libcapstone remote submodule in git, .gitignore file for build artifacts

Former-commit-id: 3b4a2c31fdf90099b633d06ad919a840129e5a03

.gitignore

+build/
+include/elfio/
+include/targ-config.h
+third_party/ELFIO/
+
+

.gitmodules

+[submodule "libcapstone"]
+	path = libcapstone
+	url = https://github.com/aquynh/capstone.git

libcapstone @ 5e184ec3

+Subproject commit 5e184ec3c7fe3b3333639f4962762cce4e971888