Update to 4.016
Changelog:
* Verilator 4.016 2016-06-16
*** Add --quiet-exit, bug1436. [Todd Strader]
**** Error continuation lines no longer have %Error prefix.
**** Support logical equivalence operator <->.
**** Support VerilatedFstC set_time_unit, bug1433. [Pieter Kapsenberg]
**** Support deferred assertions, bug1449. [Charles Eddleston]
**** Mark infrequently called functions with GCC cold attribute.
**** Fix sign-compare warning in verilated.cpp, bug1437. [Sergey Kvachonok]
**** Fix fault on $realtime with %t, bug1443. [Julien Margetts]
**** Fix $display with string without %s, bug1441. [Denis Rystsov]
**** Fix parameter function string returns, bug1441. [Denis Rystsov]
**** Fix invalid XML output due to special chars, bug1444. [Kanad Kanhere]
**** Fix performance when mulithreaded on 1 CPU, bug1455. [Stefan Wallentowitz]
**** Fix type and real parameter issues, bug1427, bug1456, bug1458. [Todd Strader]
**** Fix build error on MinGW, bug1460. [Richard Myers]
**** Fix not reporting some duplicate signals, bug1462. [Peter Gerst]
**** Fix --savable invalid C++ on packed arrays, bug1465. [Alex Chadwick]
**** Fix constant function return of function var, bug1467. [Roman Popov]
* Verilator 4.014 2019-05-08
*** Add --trace-fst-thread.
**** Support '#' comments in $readmem, bug1411. [Frederick Requin]
**** Support "'dx" constants, bug1423. [Udi Finkelstein]
**** For FST tracing use LZ4 compression. [Tony Bybell]
**** Add error when use parameters without value, bug1424. [Peter Gerst]
**** Auto-extend and WIDTH warn on unsized X/Zs, bug1423. [Udi Finkelstein]
**** Fix missing VL_SHIFTL_ errors, bug1412, bug1415. [Larry Lee]
**** Fix MinGW GCC 6 printf formats, bug1413. [Sergey Kvachonok]
**** Fix test problems when missing fst2vcd, bug1417. [Todd Strader]
**** Fix GTKWave register warning, bug1421. [Pieter Kapsenberg]
**** Fix FST enums not displaying, bug1426. [Danilo Ramos]
**** Fix table compile error with multiinterfaces, bug1431. [Bogdan Vukobratovic]
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