Using tasker you can accomplish this and more fairly easily once you know how to use it. To solve the whole phone ringing while you are in a meeting you have a few options with how to do it in Tasker. You can choose to silence your phone while in meetings, set it to vibrate, block all phone calls (probably not the best choice) or send them all to voicemail. I will go through how to create a profile for the latter.
First, Create a new profile:
Next select State, then App, and then Calendar Entry
For the Calendar entry settings you need to make sure to select No for availability and then you can click the magnifying glass next to Calendar to select which calendar it should be referencing. Then click the check mark.
Now to create a task to do during that meeting. Select New task and then click the plus (+) sign in the lower left corner.
For the action select Phone and then Select End Call and then the check mark
Once you have done that you can click the check mark to close and save the task. Go to the Profiles tab at the top, then click on your Profile you created and long press on the Context below it (the Calendar setting on the left). This should bring up a Context menu. Select Add and then Event.
From Events select Phone and then Phone Ringing.
Now you have a Profile to push phone calls to voicemail when you are in meetings.