Skippable ipk & script generation

[timothyqiu]

Added options --no-sh and --no-ipk to skip the generation of swjsq_wget.sh and swjsq_0.0.1_all.ipk. Without these options, the behavior is not changed.

This is a feature requested in #34 and my daily usage 😄

[fffonion]

In some embedded distributions (like openembedded) argparse is not shipped with python installation, it would be better to wrap import argparse with try...except and disable this feature for these users.

[timothyqiu]

OK, I'll change it to use getopt instead.

[fffonion]

getopt is good alternative but the code can be annoying. My suggestion is to read environment variables if argparse is not available, if you insists enabling this feature for all distros.😀

[timothyqiu]

Done. Got rid of argparse and always use getopt...

btw, since with open(...) as f pattern is used, the minimal python version support is 2.6, right?

[fffonion]

getopt introduces too much irrelevant code. As I suggested before, it would be better to keep using argparse but at the same time adding an alternative for users who don't have this module (eg. use environment variables). In the way codes can be clean🌚

[timothyqiu]

IMHO, it is inappropriate to change the interface depending on the Python version used. (i.e. Use command line options if 2.7 or later, use environment variables if 2.6 or before) There're already weird things happening in Python 3 support which needs to be fixed. Doing so further breaks the interface consistency between 2.6.X and 2.7.X apart, also yielding not-so-clean code.

In the case of "introducing too much irrelevant code", the common solution is simple and pretty obvious: move those code into a separate module. But, if I understand correctly, this project is standalone (no 3rd part library) and single-filed on purpose, so newbies could easily use it. Therefore, it is destined to be including various irrelevant code as time goes on.

If you still think this pull request unacceptable, feel free to close it. I'll keep this in my own fork instead. 😞