JVET-S0100 Aspect 3: constraints on vps_dpb_max_tid and vps_hrd_max_tid depending on vps_ptl_max_tid

Merge

These changes should not affect any bitstream

gci_no_rectangular_slice_constraint_flag,
gci_one_slice_per_subpic_constraint_flag,
gci_no_subpic_info_constraint_flag and remove
gci_one_subpic_per_pic_constraint_flag

(1) move frame_only_constraint_flag and single_layer_constraint_flag outside the GCI syntax structure into the PTL syntax structure
(2) rename single_layer_constraint_flag to multi_layer_enabled_flag
(3) change ptl_alignment_zero_bit to ptl_reserved_zero_bit

Also fixes #738

VUI modifications including VUI length, moving two flags from GCI to
VUI, reordering VUI variables to follow syntax elements

When pic_width_in_luma_samples is equal to pic_width_max_in_luma_samples and pic_height_in_luma_samples is equal to pic_height_max_in_luma_samples, the value of pps_conformance_window_flag shall be equal to 0