Initial commit of rewrite/refactoring with...

a working class for inpayment slips
a skeleton class for inpayment slips as pdf
an updated composer.json
some new examples
Removed function setPaymentData
Added function getCodeLine for getting the code line at the bottom
Added helper function getAccountDigits
Added functions getAmountFrancs & getAmountCents
Some minor changes in the examples
Added some class wide todos in SwissInpaymentSlip
Added a second parameter for getCompleteReferenceNumber for filling up with leading zeros
Minor changes in the examples
Implemented a fully working SwissInpaymentSlipPdf, yet to optimize in many ways though
Optimized line writing code in SwissInpaymentSlipPdf
Added some setters in SwissInpaymentSlipPdf
Other minor improvements in SwissInpaymentSlipPdf
Minor changes in example file
Minor changes in SwissInpaymentSlip class header
Reorganized Classes

Renamed SwissInpaymentSlip to SwissInpaymentSlipData
Renamed SwissInpaymentSlipPdf to SwissInpaymentSlip
Removed FPDF specific code from SwissInpaymentSlipPdf into new SwissInpaymentSlipFpdf

Updated two example files
Created an abstract base class for SwissInpaymentSlipFpdf named SwissInpaymentSlipPdf.
Hopefully this will allow to use other pdf engines than FPDF
Removed a left over function in SwissInpaymentSlipPdf
Fixed several bugs
Improved code flexibility
Changed private members and methods to protected because this helps to extend this class mor easily
Improved performance by utilizing cached hex2rgb responses and conditional coloring
Added TCPDF to composer.json
Created two examples to test the classes with TCPDF
Removed original CreditSlip class
Added link to official standardisation document of SIX interbank clearing to SwissInpaymentSlipData.php
Removed unused Exception import in SwissInpaymentSlipData.php
Removed obsolete TODOs and added some new ones in SwissInpaymentSlipData.php
Fixed som typos and removed some white lines in SwissInpaymentSlipData.php
Improved performance of modulo10 function by extracting array table
Switched parameter order in SwissInpaymentSlipPdf::createCell() and its implementations
Removed unused variable assignment in SwissInpaymentSlipPdf::createInpaymentSlip()
Added inpaymentSlipData as mandatory parameter to SwissInpaymentSlip constructor
Removed SwissInpaymentSlip::createInpaymentSlipData()
Updated some comments in SwissInpaymentSlip
Reverted some test changes in SwissInpaymentSlip
Added some TODOs in SwissInpaymentSlip
Added names to the elements array in SwissInpaymentSlip::getAllElements()
Completely reworked the examples, deleted obsolete ones, created an order (kind of a walk through)
Fixed wrong output file name in example 04-01....
Added phpunit config file
Added phpunit test stubs with some few implemented tests in them
Added a basic Travis config file