Add .gitignore files for binaries under libs/ and assets/raw/

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
travis: Update to use NDK r10d; don't delete jar/so files

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
external: Build curl binary with -pie

We will use the run_pie helper from Chromium/OpenConnect to execute it
on ICS.  JB+ can run PIE binaries without a helper.

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
OpenConnectManagementThread: Use run_pie to wrap curl on ICS

Now that curl is a PIE binary, it won't run as-is on ICS.  Before
connecting, write out a wrapper script that either invokes curl-bin
(a PIE ELF binary) directly, or uses run_pie to execute it via dlopen().

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>