Add python3.5-dev package to travis
Add python3.5-dev package to travis

Change-Id: Iaa1222f487972c99255fffe087fd16d56f54933c

hashems/Mobile-Cloud-Development-Projects,hashems/Mobile-Cloud-Development-Projects,BrandonY/python-docs-samples,JavaRabbit/CS496_capstone,hashems/Mobile-Cloud-Development-Projects,sharbison3/python-docs-samples,BrandonY/python-docs-samples,canglade/NLP,GoogleCloudPlatform/python-docs-samples,GoogleCloudPlatform/python-docs-samples,JavaRabbit/CS496_capstone,BrandonY/python-docs-samples,GoogleCloudPlatform/python-docs-samples,hashems/Mobile-Cloud-Development-Projects,canglade/NLP,canglade/NLP,sharbison3/python-docs-samples,BrandonY/python-docs-samples,canglade/NLP,JavaRabbit/CS496_capstone,GoogleCloudPlatform/python-docs-samples,sharbison3/python-docs-samples,JavaRabbit/CS496_capstone,sharbison3/python-docs-samples