Updates to __init__ and poll()

[wcwong]

• Closes #5
• Added pwcacheexpire to init to allow adjustment of the cache time
• Added timeout to init to allow adjustment of the http timeout
• added force to pol() to bypass the cache regardless of the timeout
• moved the check for the vitals to after the cache check (minor optimization)

[wcwong]

Let me know if I got this right...

[jasonacox]

Thank you @wcwong !! Great job!