Fix Travis Setup for rustc and kcov

[ghost]

Using the travis.yml setup from the README.md results in the following failures on Travis:
rust stable Linux
rust beta Linux
rust nightly Linux

The builds run again by enabling sudo and removing the link-dead-code flag:
rust stable Linux
rust beta Linux
rust nightly Linux

This issue mentions rustc panicking when using the link-dead-code flag
This issue mentions kcov failing when not using sudo

[sunjay]

Thanks for creating this PR! Could you modify the repository's .travis.yml file in addition to the README.md? We try to keep those in sync. 😄

[ghost]

Sure thing!
I completely forgot about the actual .travis.yml file.
I'll fix it as soon as I get home.

[codecov]

Codecov Report

Merging #10 into master will increase coverage by 7.4%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           master      #10     +/-   ##
=========================================
+ Coverage   76.47%   83.87%   +7.4%     
=========================================
  Files           1        1             
  Lines          34       31      -3     
=========================================
  Hits           26       26             
+ Misses          8        5      -3

Impacted Files	Coverage Δ
src/lib.rs	83.87% <0%> (+7.4%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 68fab58...f477f18. Read the comment docs.

[ghost]

The README.md and .travis.yml files should now be in sync.

[sunjay]

Thank you!