Previously device tests included information such as access point SSID/password at compile time. This made it difficult to compile test binaries once and then send them to multiple test runners for execution.
This change adds a command to the test library to set environment variable on the target device: “setenv key value”. C library setenv/getenv facility is used to store variables.
Test runner, tests, and makefile are updated to use this functionality.
* tests/device/Makefile: use bourne shell compatible "." instead ot "source" (ubuntu's dash does not understand it)
* tests/device: make BEGINTIMEOUT a new error return value instead of a test-process-breaking exception
