Also fixed get latest image logic in image_to_vm and allowed for using the most recent image in cros_run_vm_test to follow other shell convention of using latest.
Change-Id: I60ed4c03d609500da7f6ae34ef57ba2e32f4b0bb
BUG=
TEST=Tested by running image_to_vm with --full and cros_run_vm_test with suite_Smoke
Review URL: http://codereview.chromium.org/3597001
Change-Id: I63bdcaa3630c179d407310f6544c102f5353fa4d
BUG=5530
TEST=Ran both cros_run_vm_test and new script and had the latter update successfully.
Review URL: http://codereview.chromium.org/3427011
Change-Id: I758c93596d5cbdd6b52b9acc82f4d6e19a326c9f
BUG=5518
TEST=Tested using all the options. All tests listed in the file pass.
Review URL: http://codereview.chromium.org/3107039