s2e_printf() API

Wraps s2e_message in a printf-like function.
Useful to print format strings.

Signed-off-by: Vitaly Chipounov <vitaly.chipounov@epfl.ch>
Fixed init_env Makefile.

- -ldl must come at the end
- added passing of custom C flags

Signed-off-by: Vitaly Chipounov <vitaly.chipounov@epfl.ch>
Reworked parsing of /proc/self/maps and module registration.

- Fixes various bugs
- Generates verbose logs to console output

Signed-off-by: Vitaly Chipounov <vitaly.chipounov@epfl.ch>
Got rid of ugly hack for parsing process maps in s2e.h

Signed-off-by: Vitaly Chipounov <vitaly.chipounov@epfl.ch>
Updated documentation for execution tracing.

Use now init_env.so instead of a bunch of convoluted hacks to the source.

Signed-off-by: Vitaly Chipounov <vitaly.chipounov@epfl.ch>