fix #1165 npm start running grunt build twice

It also refactors package.json
feat #1167 External CSS property for skins

This commit introduces a new property for skins that lets you load and use external css files.
feat #1168 New configuration for Icon Widget

When there is not a sprite url defined, the icon widget configuration is composed by a list of css classes that will be added to the html element generated.
fix  #1149 0 was not considered as an existing value in the mandatory validator
fix #1164 Some dropdowns in the flat skin are larger than expected
fix #1172 null bound value in @aria:CheckBox triggers an exception
fix #1166 Support for external hash change in page engine

When navigation is set to `hash` in the site configuration, it is now possible to change the hash manually without compromising the back/forward navigation.
Before this commit, after manually changing the hash and then navigating away to another page, it was impossible to correctly go back because the manually added hash was not correctly mapped to a page.
fix #1174 Refactoring border-radius property for widgets

Adding a macro to refactor the code for the border-radius property.
fix #1170 root map not taken into account for cssFolderPath

This commit fixes a regression introduced by commit 96c3f0591012d316db5de8325225645449ee26a7:
the root map is not taken into account for the computation of
the cssFolderPath property in CSS templates.
fix #1181 incomplete fast normalization in case of recursive bean definitions
fix #1177 Pointer cursor on Tab widget

The cursor CSS property on top of the Tab widget is now set to `cursor` unless the tab is disabled.
fix #1180 Limit call stack in IE

When the `loadFile` method of singleton `aria.core.DownloadMgr` is called, if the file is already available in the AT cache the callback is called synchronously. A big height for the dependency tree of a class leads to a growth of the function call stack which can transcend the limit imposed by some browsers, which leads to an error.

This commit adds a limitation the number of nested synchronous calls to the `loadFile` method in Internet Explorer (64bit), setting a timeout to break javascript execution when the limit is exceeded.
feat #1173 Input field focus on label click
close #1173
feat #1176 New skin properties for Dialog widget

Adding the possibility to define new skin properties for the dialog title bar.
The properties added are:
- titleBackgroundColor
- titlePadding
- titleBorder
- titleBorderStyle
- titleBorderColor
- titleBorderRadius

Close #1176
feat #1182 vertical alignment for the button widget
fix #1175 Splitter borderWidth skin property not properly handled
feat #1183 implementation of synchronous XHR requests
a new property has been added to aria.modules.RequestBeans.RequestObject and to aria.core.CfgBeans.IOAsyncRequestCfg, and the request method of aria.core.transport.BaseXHR class has been modified.
Close #1183
fix #1193 async dependency load breaks sync method
all the dependencies have to be loaded before using the sync request, because otherwise the async Aria.load method would break the sync request behaviour.
An error message has been added and another strategy is used for the tests (filters instead of aria.core.IO.asyncRequest mockup).
1.6.2
feat #1221 innerHeight is no longer mandatory for the vertical alignment in frames