Enable multiple arguments in SM and RM

Enable multiple arguments in SM and RM

SM and RM can receive multiple parameters, but the code only was accepting
only one. This patch join the code of set and reset modes (SM and RM) in a
common function and uses a loop which deals with all the arguments of the
sequence. This patch improves xterm and vt100 compability.
---
 st.c |  180 ++++++++++++++++++++++++++++--------------------------------------
 1 file changed, 76 insertions(+), 104 deletions(-)