fix(ngShow): ensure that the display property is never set to block

Fixes #7707
chore(jqLite): remove special characters from the expando property

Having special characters in the expando property created a memory bloat.
See https://code.google.com/p/chromium/issues/detail?id=378607#c6 to reproduce

Closes #7701
test(jqLite): adapt tests to new expando name