congruency: template created
math: congruency works for gcd(a,m) = 1
math: number - function for string -> integer conversion
decomposition: improvements

now uses math.number
corrected leading zeros in number
invalid input no longer clear previous calculation
math: negative numbers implemented

primes work for negative numbers
nsd, nsn work
decomposition works

euklid, approximateFractions and congruency require positive integers
nsd_nsn accepts negative numbers
nsn_nsn: ignores leading zeros
euklid: negative and invalid input solved

invalid input doesn't clear calculation
invalid input gets cleared
approximate_fraction improvements + added comments

incorrect input (negative integers, b = 0) ignored and cleared
now uses math.number

few comments for extra clarity
congruency: linked + working for gcd(a, m) = 1

linked functionality to ui
fixed an error when calculating gcd - parameter should be list, not two numbers
congruency works for gcd(a, m) > 1
improved & cleaned controllers code

values conversion and validation separated to functions
scope variables added to values object to avoid issues with child scopes