add a readme for python binding

python/README.md

@@ -0,0 +1,21 @@
+Provide a python binding to launch symsan-instrumented binary, receive events, parse constraints, and solve constraints.
+
+```
+static PyMethodDef SymSanMethods[] = {
+  {"init", SymSanInit, METH_VARARGS, "initialize symsan target"},
+  {"config", (PyCFunction)SymSanConfig, METH_VARARGS | METH_KEYWORDS, "config symsan"},
+  {"run", (PyCFunction)SymSanRun, METH_VARARGS | METH_KEYWORDS, "run symsan target, optional stdin=file"},
+  {"read_event", SymSanReadEvent, METH_VARARGS, "read a symsan event"},
+  {"terminate", (PyCFunction)SymSanTerminate, METH_NOARGS, "terminate current symsan instance"},
+  {"destroy", (PyCFunction)SymSanDestroy, METH_NOARGS, "destroy symsan target"},
+  {"reset_input", InitParser, METH_VARARGS, "reset the symbolic expression parser with a new input"},
+  {"parse_cond", ParseCond, METH_VARARGS, "parse trace_cond event into solving tasks"},
+  {"parse_gep", ParseGEP, METH_VARARGS, "parse trace_gep event into solving tasks"},
+  {"add_constraint", AddConstraint, METH_VARARGS, "add a constraint"},
+  {"record_memcmp", RecordMemcmp, METH_VARARGS, "record a memcmp event"},
+  {"solve_task", SolveTask, METH_VARARGS, "solve a task"},
+  {NULL, NULL, 0, NULL}  /* Sentinel */
+};
+```
+
+Currently only z3 solver is supported, will merge jigsaw and i2s later.