Remove asterisk from citation section. (#118)

Asterisk for co-first author messes up alphabetical ordering in references section.

README.md

@@ -41,7 +41,7 @@ If you use the Habitat platform in your research, please cite the following [tec
 ```
 @article{habitat19arxiv,
   title =   {Habitat: A Platform for Embodied AI Research},
-  author =  {{Manolis Savva*}, {Abhishek Kadian*}, {Oleksandr Maksymets*}, Yili Zhao, Erik Wijmans, Bhavana Jain, Julian Straub, Jia Liu, Vladlen Koltun, Jitendra Malik, Devi Parikh and Dhruv Batra},
+  author =  {Manolis Savva, Abhishek Kadian, Oleksandr Maksymets, Yili Zhao, Erik Wijmans, Bhavana Jain, Julian Straub, Jia Liu, Vladlen Koltun, Jitendra Malik, Devi Parikh and Dhruv Batra},
   journal = {arXiv preprint arXiv:1904.01201},
   year =    {2019}
 }

docs/source/tutorials/quickstart.md

@@ -101,7 +101,7 @@ If you use habitat in your work, please cite:
 ```text
 @article{habitat19arxiv,
   title =   {Habitat: A Platform for Embodied AI Research},
-  author =  {{Manolis Savva*}, {Abhishek Kadian*}, {Oleksandr Maksymets*}, Yili Zhao, Erik Wijmans, Bhavana Jain, Julian Straub, Jia Liu, Vladlen Koltun, Jitendra Malik, Devi Parikh and Dhruv Batra},
+  author =  {Manolis Savva, Abhishek Kadian, Oleksandr Maksymets, Yili Zhao, Erik Wijmans, Bhavana Jain, Julian Straub, Jia Liu, Vladlen Koltun, Jitendra Malik, Devi Parikh and Dhruv Batra},
   journal = {arXiv preprint arXiv:1904.01201},
   year =    {2019}
 }