Cygwin-style is really only /cygpath/xxx and IDF doesn't support these. Closes https://github.com/espressif/esp-idf/pull/1033
Mostly useful for Eclipse (where accidentally running interactive config hangs the build), but also good for CI and other automated build systems.
Includes splitting the Windows Eclipse setup doc into a separate page, as it has so many additional steps. Addresses github #17 and #166 https://github.com/espressif/esp-idf/issues/17 https://github.com/espressif/esp-idf/issues/166