Add processMem() to process.go

Uses Cgo to get the pagesize
Move exported functions to the top of the file
Remove rss from cpustat
Replace numberofCPUs() in cpu.go with runtime.NumCPU()
Fix charToStr() returning strings longer than necessary
Change GetProcessInfo to return a chan map[string]ProcessInfo

Earlier it returned map[int].
This is because json.Marshal will only accept maps that have keys as strings