Fixed crash when the 1Password extension is shown before the web view is fully loaded.

This should resolve #116
Merge branch 'master' into bugfix/fix-crash-when-the-extension-is-called-before-the-webview-is-fully-loaded

Conflicts:
	OnePasswordExtension.m
Merge branch 'master' into bugfix/fix-crash-when-the-extension-is-called-before-the-webview-is-fully-loaded
Replaced "Get" with "Obtain"
Merge pull request #120 from AgileBits/bugfix/fix-crash-when-the-extension-is-called-before-the-webview-is-fully-loaded

Fixed crash when the 1Password extension is shown before the web view is fully loaded.