Fix page title and add cursor lines

[davidmigloz]

This PR fixes one bug and adds a handy feature:

• The title of the page wasn't being updated after loading a different document. Now it properly updates it.
• A horizontal and a vertical line have been added to the cursor to make it easier to match the Y-axis (task name) and the X-axis (time horizon).

I also made some improvements to the Google Sheet template:

• Improved the styling of the document
• Added URL column which contains a hyperlink to the page of the task in your task management system. It concatenates a configurable base URL plus the TaskId (e.g. https://myjira.atlassian.net/browse/TASK-1)
• Added conditional formatting to the Percent Complete column. 0% completed tasks will be in grey, 1-99% completed tasks will be in yellow and 100% completed tasks will be in green.
• Adds a Today task that allows you to easily find the current date in the Gantt diagram

You can find my template here:
https://docs.google.com/spreadsheets/d/1DSecFxmUCgOAJ0mvbT1X21v68I0Vn_AWXKH7z9ruYc0