Added day 4 part 1

Author: Gentleman1983

build.gradle

@@ -4,7 +4,7 @@ plugins {
 
 // project meta data
 group 'de.havox_design.aoc2015'
-version '0.3.0'
+version '0.3.1'
 
 // Switch to gradle "all" distribution.
 wrapper {

day04/README.md

@@ -0,0 +1,17 @@
+# Day 4: The Ideal Stocking Stuffer
+Santa needs help [mining](https://en.wikipedia.org/wiki/Bitcoin#Mining) some AdventCoins (very similar to 
+[bitcoins](https://en.wikipedia.org/wiki/Bitcoin)) to use as gifts for all the economically forward-thinking little 
+girls and boys.
+
+To do this, he needs to find [MD5](https://en.wikipedia.org/wiki/MD5) hashes which, in 
+[hexadecimal](https://en.wikipedia.org/wiki/Hexadecimal), start with at least **five zeroes**. The input to the MD5 
+hash is some secret key (your puzzle input, given below) followed by a number in decimal. To mine AdventCoins, you 
+must find Santa the lowest positive number (no leading zeroes: `1`, `2`, `3`, ...) that produces such a hash.
+
+For example:
+* If your secret key is `abcdef`, the answer is `609043`, because the MD5 hash of `abcdef609043` starts with five 
+zeroes (`000001dbbfa...`), and it is the lowest such number to do so.
+* If your secret key is `pqrstuv`, the lowest number it combines with to make an MD5 hash starting with five zeroes 
+is `1048970`; that is, the MD5 hash of `pqrstuv1048970` looks like `000006136ef...`.
+
+Your puzzle input is `bgvyzdsv`.

day04/src/main/resources/day04.txt

@@ -0,0 +1 @@
+bgvyzdsv

day04/src/test/resources/part1sample1.txt

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+abcdef

day04/src/test/resources/part1sample2.txt

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+pqrstuv