release v0.1.8
re-address conditional menu-items

previous code for issue #10 only handled the initial conditional, but
didn't consider when the conditional changes and bindings are
re-triggered. add a test for later condition and re-address
add disabled state for ic-menu-item

allow a menu-item to be enabled (the default state). when not enabled, set
aria-disabled on menu item and update default styles. add
on-disabled-select action to be triggered when user selects a disabled
menu item.
Merge pull request #13 from knomedia/add-disabled-state-for-menu-items

add disabled state for ic-menu-item
Merge pull request #12 from knomedia/revisit-conditional-items

re-address conditional menu-items
add travis configuration
release version 0.1.9
add travis badge to README.md
fix grunt command on travis
update ic-styled
release v0.1.11