Update .gitignore

shlr/sdb/src/libsdb.so*
shlr/capstone/

Also there is a `"main" file in the root directory which is added when using ./sys/install.sh`,
`main: broken symbolic link to `/home/maijin/radare2/doc/hud /usr/lib/radare2/0.9.8.git/hud/main'`