Various flags and small fixes for troubleshooting and speed tests

[ionescu007]

• Add a feature to control if 128K, 4MB, or 16MB reads should be supported [-no16M, -no4M, -no128K]. Allows trying out different read mechanisms potentially for troubleshooting or speed measurement. Also return status on which read sizes were used.
• "Force" flag should not cause bail out if 16MB consecutive region has failed -- there may be (and often are) MMIO gaps after a while which still contain OS data.
• Use SwitchToThread instead of Sleep(0), since that's the actual behavior desired.
• Use 500ms pipe timeout
• Fix a typo
• Support full memory read without an actual "dump" [-noout] to disk. Useful for testing/speed measurement/demo.