SQOOP-3427 Add Travis badge to the README

[Fokko]

We all love badges: https://jira.apache.org/jira/browse/SQOOP-3427

[fszabo2]

Hi @Fokko,

Thanks for submitting this patch!
Could you remove the old README.txt file as well so we don't duplicate information?
(Or do you think we should keep it?)

In any case, badges are awesome!

[Fokko]

Thanks for looking into this @fszabo2

I've removed the old README. I think we should get rid of it since it is almost the same as the new one.

[Fokko]

I also took the liberty to include Koen's work in #31 into this PR.

[fszabo2]

Hi @Fokko,

Sorry for my late responses, I have quite limited bandwidth these days for Sqoop.

Anyway, could you please rebase this on the current trunk, so we can see if your fix for the CI took effect?

[Fokko]

Thanks for taking the time. I've rebased the PR.

Probably I'll do a couple of more PR's in the upcoming days to fix the compiler warnings, make better use of try-with-resources and bumping some of the dependencies to fix security issues.

[szvasas]

Hi @Fokko,

I have submitted a PR for your branch with my suggestions: https://github.com/Fokko/sqoop/pull/1/files
I basically renamed COMPILING.txt to COMPILING.adoc so GitHub will format it by default and I refer it from README.md.

[Fokko]

Thanks @szvasas

Sorry for taking so long, I was a bit busy lately.