Convert LF build to run E2E tests on Windows

This will be a series of commits changing the build-lf.xml step by step,
setting up the new system while keeping the old system in place until
the new system is ready, so the project will continue to build at all times.
Fix build-lf.xml syntax error
Fix path to node_modules in build-lf.xml
LF build: be more robust against missing dirs

If the node_modules/protractor/selenium directory isn't present, the
build script shouldn't fail.
LF build: run Selenium from build dir, not install

Since we're running the Selenium tests from the Windows build agent, the
install dir (/var/www/whatever) will not exist. Instead, we need to run
Selenium and Protractor from the build directory.
LF build: tweak path to Protractor script
Fix URL for Protractor tests on LF
LF build: explicitly specify path to Chrome driver

This is specifically for running the E2E tests on Windows, and no
attempt has been made to make this step cross-platform.
Specify target for unzip step
Make chromedriver path less Windows-specific

By specifying the chromedriver location in the build parameters in
TeamCity, we should be able to make this cross-platform instead of
completely Windows-specific.
Delete cruft accidentally added in previous commit
Specify chromedriver location for Selenium JAR cmd
LF build: unzip Chrome driver at an earlier step
Update frontpage slideshow

Made slideshow consist of 4 panels.  Kept teamwork, and added 3 screenshots of LF features
LF build: Check if Selenium is running
Rename PNG files png for case-sensitive filesystem
Clear username after adding users to project

As per suggestion at https://trello.com/c/ZQxd60mq/
Replace email with username in user management

This fulfills two different suggestion cards at once:
 * https://trello.com/c/cIxEv1Fp/
 * https://trello.com/c/50JkXdPW/
Update SIL International logo and copyright to conform

The new July 2014 SIL International logo has specific requirements on blue border.  png file has been updated accordingly (for future usage).  Due to the contrast with the LF blue footer, I've removed the logo image.
line breaking for footer