Integrating mapmerge2 checks into Travis (#5616)

Okay, this update is kinda big. Summary:

- Trimmed unused keys in Exodus telecomms

- Adds script that will run mapmerge2 on Travis to check branch for unused keys or key overflow, etc.

- Fixes matching indentation style in tag-matcher and converts it to use Python 3.6

- Converts mapmerge2 to be used by Python 3.4 and above. Instead of 3.6

- Removes Windows 1252 characters from Communication-blackout.dm that were not able to be seen in UTF-8 format.

Note: the last commit will fail because currently main level is broken

Example of no map issues:
![2018-11-15_li](https://user-images.githubusercontent.com/25555314/48592180-0fd7be80-e8fc-11e8-80b9-cd5af32540e3.jpg)

Example of issues:
![2018-11-15_li 2](https://user-images.githubusercontent.com/25555314/48592190-15cd9f80-e8fc-11e8-99bd-6da4b4c2b9d8.jpg)

code/modules/events/communications_blackout.dm

@@ -3,11 +3,11 @@
 
 /datum/event/communications_blackout/announce()
 	var/alert = pick(	"Ionospheric anomalies detected. Temporary telecommunication failure imminent. Please contact you*%fj00)`5vc-BZZT", \
-						"Ionospheric anomalies detected. Temporary telecommunication failu*3mga;b4;'1v¬-BZZZT", \
+						"Ionospheric anomalies detected. Temporary telecommunication failu*3mga;b4;'1v-BZZZT", \
 						"Ionospheric anomalies detected. Temporary telec#MCi46:5.;@63-BZZZZT", \
 						"Ionospheric anomalies dete'fZ\\kg5_0-BZZZZZT", \
-						"Ionospheri:%£ MCayj^j<.3-BZZZZZZT", \
-						"#4nd%;f4y6,>£%-BZZZZZZZT")
+						"Ionospheri:% MCayj^j<.3-BZZZZZZT", \
+						"#4nd%;f4y6,>%-BZZZZZZZT")
 
 	for(var/mob/living/silicon/ai/A in player_list)	//AIs are always aware of communication blackouts.
 		A << "<br>"