[FLOW3-general] Neos: Add a package

[indira]

Hi, 

after this first experience (adding a custom Flow3 package to neos) I took 
the following notes:

1- First run the core:migrate command specifying the package key (we can 
get some errors for not finding git, but those are ok)
2- Check the structure of the package (everything inside Classes should be 
inside Classes/YourVendor/YourPackage/Controller, check Package.php in case 
you have to change any path) 
3- Check in your package there is no "Flow3", it was supposed to be 
replaced with "flow" after runnig the migration tool.
4- Clear the cache
5- Check php error log

Thanks to Christian for his help.
Hope this helps to others. 
Regards,
Indira.